Detection of antibodies to total histones and their subfractions in systemic lupus erythematosus patients and their asymptomatic relatives

Sera drawn from 75 patients with systemic lupus erythematosus, 141 healthy relatives (from the families of 51 patients), and 115 healthy control subjects were examined, by enzyme‐linked immunosorbent assay, for IgG and IgM antibodies to total histones and their subfractions. Compared with the controls, statistically significant numbers of patients and their relatives had antihistone antibodies of both isotypes. Among the relatives, the sera from females, notably sisters of the patients, contained the highest levels of anti–total histone antibody. Anti‐H2A/H2B and H3 antibodies were most prevalent among the lupus patients, but many of the relatives had IgM anti‐H4 antibodies. These findings indicate that antihistone antibodies can serve as a genetic marker in patients with systemic lupus erythematosus.